In its early stages prostate cancer stays in the prostate and is not life-threatening, but without treatment spreads to other parts of the body and eventually causes death. A major challenge is thus to recognize and target the molecular mechanisms allowing prostate tumor cells to spread. Our long-term goal is to identify and characterize mechanosensitive and Ca2+-dependent mechanisms that regulate tumor cell migration and invasiveness. Our research is based on the emerging concept that pathophysiologically enhanced cell motility is a critical step in the metastatic cascade leading to migration and invasion by tumor cells. This project focuses on the mechanosensory Ca2+-permeable cation channels (MscCa) that transduce membrane stretch into a Ca2+ influx, thus providing feedback between cell extension and Ca2+-dependent mechanisms that generate traction forces and regulate cell adhesions. We hypothesize that specific MscCa properties acquired during tumor cell transformation allow it to coordinate migration and invasiveness. We will test this hypothesis via two specific aims comparing the functional and molecular expression of MscCa in normal human prostate epithelial and in prostate tumor cell derivatives showing transformed motility and metastatic potential vs. their parent cell lines. Aim 1 will use patch-/pressure-clamp techniques and confocal immunofluorescence microscopy to compare MscCa's properties, (including conductance, gating dynamics, membrane surface distribution, and interaction with other Ca2+-sensitive channels) between "normal" and transformed" cells. Aim 2 will use time-lapse video microscopy and fluorescent Ca2+ imaging to measure fluctuations in intracellular [Ca2+] in order to determine how MscCa and other Ca2+-sensitive channels regulate cell migration. Cell migration plays a critical role in the pathogenesis of prostate cancer, so identifying and characterizing the MscCa, a rate-limiting regulatory molecule in cell migration, should introduce an important new therapeutic target for pharmacological and genetic treatments that are urgently required to prevent the spread and mortality of prostate cancer.